Patent application title: FASTENER SAFETY RETENTION

Abstract:

A safety fastener capable of retaining portions thereof in the event of
breakage is disclosed. The safety fastener includes a through hole along
the longitudinal axis of a shaft. A secondary member, such as a wire
rope, may be disposed within the through hole. Capturing members, such as
balls sized larger than the through holes may be swaged or crimped to
both ends of the secondary member, thereby capturing the shaft between
them. In the event of breakage, portions of the shaft may remain
substantially in place being confined by the secondary member and
capturing members. Inspection of the safety fastener may include
determining that the secondary member is loose relative to the shaft,
thereby indicating that no gaps or separation has occurred in the shaft.

Claims:

1. A fastener comprising:a shaft, wherein said shaft includes a first end
and a second end;a through hole through said shaft; anda secondary
member, said secondary member including a first portion extending beyond
said first end of said shaft, a second portion extending beyond said
second end of said shaft and a third portion disposed within said through
hole.

2. The fastener of claim 1 further comprising:a first capturing member
connected to said first portion of said secondary member; anda second
capturing member connected to said second portion of said secondary
member, wherein said first and second capturing members each have a cross
dimension in a plane perpendicular to a central axis of said through hole
that is greater than a diameter of said through hole.

3. The fastener of claim 1, wherein said secondary member is free from
direct securement to said shaft.

4. The fastener of claim 1, wherein said shaft includes a head disposed at
said first end of said shaft.

5. The fastener of claim 1, wherein said shaft has a longitudinal axis,
wherein said through hole is through an entire length of said shaft along
said longitudinal axis, wherein said third portion is disposed within
said through hole along said entire length of said shaft.

6. The fastener of claim 1, wherein a ratio of a minimum outer diameter of
said shaft to a diameter of said through hole is at least 6 to 1.

7. The fastener of claim 1, wherein said secondary member is flexible.

8. The fastener of claim 2, wherein said first and second capturing
members are swaged onto said secondary member.

9. The fastener of claim 8, wherein a distance between said first and
second capturing members is greater than the length of said shaft.

10. The fastener of claim 7, further comprising:a first capturing member
positioned along said first portion of said secondary member; anda second
capturing member positioned along said second portion of said secondary
member, wherein said first and second capturing members each have a cross
dimension in a plane perpendicular to a central axis of said through hole
that is greater than a diameter of said through hole, wherein at least
one of said first and second capturing members are at least partially
formed from said secondary member.

11. The fastener of claim 1, wherein said secondary member comprises at
least one item selected from a group consisting of wire, rope, wire rope,
cable, cord, strap, and line.

13. The fastener of claim 6, wherein a maximum cross dimension of said
secondary member is less than a minimum diameter of said through hole.

14. A fastener comprising:a shaft, wherein said shaft includes a first end
and a second end, wherein said shaft has a longitudinal axis;a through
hole through the entire length of said shaft along said longitudinal
axis; anda secondary member disposed within said through hole, wherein
said secondary member is free from securement to said shaft.

15. The fastener of claim 14, further comprising:a first capturing member
connected to said secondary member; anda second capturing member
connected to said secondary member, wherein a portion of said shaft is
disposed between said first and second capturing members, wherein said
first and second capturing members each have a cross dimension in a plane
perpendicular to said longitudinal axis greater than a diameter of said
portion of said through hole between said first and second capturing
members.

16. A method of manufacturing a fastener, said method comprising:providing
a shaft having a longitudinal axis, wherein said shaft includes a through
hole through the entire length of said shaft along said longitudinal
axis;inserting a secondary member into said through hole, wherein after
said inserting step a first portion of said secondary member extends
beyond a first end of said shaft, a second portion of said secondary
member extends beyond a second end of said shaft, and a third portion of
said secondary member is disposed within said through hole along an
entire length of said shaft;forming a first capturing member positioned
along said first portion of said secondary member; andforming a second
capturing member positioned along said second portion of said secondary
member.

17. The method of claim 16, wherein said forming said first capturing
member step comprises attaching a first member to said first portion of
said secondary member, wherein said forming said second capturing member
step comprises attaching a second member to said second portion of said
secondary member.

18. The method of claim 17, wherein said attaching said first member
comprises swaging said first member, wherein said attaching said second
member comprises swaging said second member.

19. The method of claim 16, wherein at least one of said forming a first
capturing member and forming a second capturing member steps comprises
forming said at least one of said first capturing member and said second
capturing member from said secondary member.

20. A bolt comprising:a shaft, wherein said shaft includes a first end and
a second end, wherein said shaft has a longitudinal axis, wherein said
shaft includes a head disposed at said first end of said shaft, wherein
said shaft includes an externally threaded portion;a through hole through
the entire length of said shaft along said longitudinal axis;an elongate
flexible retention member, said elongate flexible retention member
including a first portion extending beyond said first end of said shaft,
a second portion extending beyond said second end of said shaft and a
third portion disposed within said through hole along an entire length of
said shaft, wherein said elongate flexible retention member is free from
direct securement to said shaft;a first capturing member connected to
said first portion of said elongate flexible retention member; anda
second capturing member connected to said second portion of said elongate
flexible retention member, wherein said first and second capturing
members each have a cross dimension in a plane perpendicular to said
longitudinal axis greater than a diameter of said through hole, wherein a
distance between said first and second capturing members is greater than
the length of said shaft.

Description:

BACKGROUND OF THE INVENTION

[0001]1. Field of the Invention

[0002]The present invention relates, in general, to hardware, and, more
particularly, to fasteners that have supplemental members operable to
indicate the status of the fastener and/or retain portions of the
fastener upon breakage of the fastener.

[0003]2. Relevant Background

[0004]It has often been desirable to position clips or brackets in
relation to fasteners in such a way as to retain portions of the fastener
in the event the fastener breaks into two or more separate pieces. Such
fastener retention systems are generally used where uncontrolled movement
of a broken portion of a fastener may lead to injury or property damage.
For example, certain bolts used in the aircraft industry may have a clip
or bracket positioned over the head of the bolt to prevent the head of
the bolt from becoming unrestrained in the event the bolt breaks.

[0005]Such fastener systems may be utilized for a variety of reasons. As
noted above, the aircraft industry may use such systems to prevent
portions of fasteners breaking loose and entering turbines or falling to
the ground below. Such fastener systems may be used to secure fasteners
used in high-speed equipment, where an unrestrained portion of a broken
fastener could be thrown from the equipment at high speed. Such fastener
systems may be used in amusement park attractions where equipment and
people may be at significant heights and/or moving at high rates of speed
where an unrestrained portion of a broken fastener could result in injury
to patrons or workers in the vicinity of the attraction.

[0006]The above-described known fastener retention systems have several
limitations. One limitation is that such systems require additional parts
beyond that of the primary fastener in order to secure the portions of
the primary fastener in the event of breakage of the primary fastener.
Furthermore, the parts may require additional labor to install beyond the
labor needed to install the primary fastener. Moreover, areas surrounding
the fastener may require features, such as tapped holes, to enable
securement of the additional parts so that they may perform the fastener
retention function. In addition, the additional parts may interfere with
visual and/or other inspection of the primary fastener.

[0007]It has also often been desirable to provide fastening systems that
may be quickly inspected to verify their operating condition. For
example, safety wire may be attached to a bolt head (e.g., running the
safety wire through the head of the bolt through a hole perpendicular to
a longitudinal axis of the bolt) to both secure the rotational position
of the bolt and to provide a visual indication of the status of the bolt
for inspection. The safety wire may be attached to a member external to
the bolt. Such a system requires additional parts to be assembled at the
location of the installation of the bolt. Attaching safety wire to a bolt
is also a labor-intensive task. Furthermore, the safety wire may need to
be removed in order to remove the bolt, requiring additional labor. For
another example, a bolt head and a corresponding proximate surface may be
correspondingly marked with alignment marks and/or a putty-like substance
(e.g., torque stripe or paint) so that any movement of the bolt head
relative to the proximate surface may be detected. Although such marking
may be quickly evaluated, such marking may provide no retention
capabilities in the event of bolt failure and may not provide information
regarding the status of the bolt below the head.

SUMMARY OF THE INVENTION

[0008]Embodiments of the present invention address the above-described
issues by providing hardware that includes a secondary member capable of
retaining portions of the hardware in the event of breakage of the
hardware. The hardware may achieve such performance without the need for
additional components that must be installed separately at the location
where the hardware is employed. Furthermore, such hardware may be easily
inspected to verify its operating condition.

[0009]The hardware may be in the form of a fastener, such as, for example,
a bolt or a pin. The secondary member may be free from direct securement
to a shaft of the fastener. In this regard, the secondary member may be
capable of remaining in tact in the event that the shaft of the fastener
fails. The secondary member may then function to retain the broken
portions of the shaft of the fastener until the breakage can be detected
and repaired.

[0010]In this manner, an easily installed and inspected fastener is
provided that provides safety retention capabilities. Such fasteners may
be stocked and installed in the same manner as non-safety fasteners, yet
provide retention capabilities in case of breakage.

[0011]In one aspect, a fastener comprises a shaft with a through hole and
a secondary member. The shaft may have a first end and a second end and
the secondary member may include a first portion extending beyond the
first end of the shaft, a second portion extending beyond the second end
of the shaft and a third portion disposed within the through hole.

[0012]In an embodiment, a first capturing member may be connected to the
first portion of the secondary member and a second capturing member may
be connected to the second portion of the secondary member. The first and
second capturing members may each have a cross dimension in a plane
perpendicular to a central axis of the through hole that is greater than
a diameter of the through hole.

[0013]In an arrangement, the secondary member may be free from direct
securement to the shaft. In an arrangement, the shaft may include a head
disposed at one of the ends of the shaft. The shaft may include a notch
near one or both of the ends of the shaft. The notch or notches may be
configured to work with corresponding clips or other appropriate hardware
to secure the fastener in place.

[0014]In an embodiment, the shaft may have a longitudinal axis and the
through hole may be through the entire length of the shaft along the
longitudinal axis. The third portion of the secondary member may be
disposed within the through hole along the entire length of the shaft.

[0015]The secondary member may be flexible. The secondary member may, for
example, comprise wire, rope, wire rope, cable, cord, strap, and/or line.
In a particular arrangement, the secondary member may comprise metal wire
rope. There may be clearance between the inside of the through hole and
the secondary member. In this regard, a maximum cross dimension of the
secondary member may be less than a minimum diameter of the through hole.

[0016]The first and second capturing members may be swaged onto the
secondary member or attached thereto in any appropriate manner. In
another arrangement, one or both of the capturing members may be at least
partially formed from the secondary member. The distance between the
first and second capturing members may be greater than the length of the
shaft.

[0017]In another aspect, a fastener is provided that comprises: a shaft
with a longitudinal axis; a through hole through the entire length of the
shaft along the longitudinal axis; and a secondary member. The secondary
member may be disposed within the through hole and may be free from
securement to the shaft. The shaft may have a first end and a second end.

[0018]In an embodiment of the current aspect, the fastener may include
first and second capturing members each connected to the secondary
member. A portion of the shaft may be disposed between the first and
second capturing members. The capturing members may be sized such that
they are incapable of passing through a portion of the through hole
between the first and second capturing members. In this regard, the first
and second capturing members may each have a cross dimension in a plane
perpendicular to the longitudinal axis greater than a diameter of a
portion of the through hole between the first and second capturing
members.

[0019]In vet another aspect, a method of manufacturing a fastener is
provided. The method may include providing a shaft having a longitudinal
axis, inserting a secondary member into a through hole through the shaft,
forming a first capturing member positioned along a first portion of the
secondary member, and forming a second capturing member positioned along
a second portion of the secondary member. The through hole through the
shaft may be disposed through the entire length of the shaft along the
longitudinal axis. The first portion of the secondary member may extend
beyond a first end of the shaft and the second portion of the secondary
member may extend beyond a second end of the shaft. A third portion of
the secondary member may be disposed within the through hole along an
entire length of the shaft.

[0020]In an embodiment, the step of forming the first capturing member may
include attaching a first member to the first portion of the secondary
member. The step of forming the second capturing member may include
attaching a second member to the second portion of the secondary member.
Attaching the first and second members may include swaging the members
onto the secondary member. In an embodiment, at least one of the forming
the first capturing, member and forming the second capturing member steps
may comprise forming the respective capturing member from the secondary
member.

[0021]In still another aspect a bolt is provided that may include a shaft
with a through hole, an elongate flexible retention member and first and
second capturing members. The shaft may have a longitudinal axis. The
shaft may include first and second ends with a head disposed at the first
end and an externally threaded portion disposed at the second end. The
through hole may be through the entire length of the shaft along the
longitudinal axis. The elongate flexible retention member may include a
first portion extending beyond the first end of the shaft, a second
portion extending beyond the second end of the shaft and a third portion
disposed within the through hole along the entire length of the shaft.
The elongate flexible retention member may be free from direct securement
to the shaft. The elongate flexible retention member may be a wire rope.
The first capturing member may be connected to the first portion of the
elongate flexible retention member and the second capturing member may be
connected to the second portion of the elongate flexible retention
member. The first and second capturing members may each have a cross
dimension in a plane perpendicular to the longitudinal axis greater than
a diameter of the through hole. In this regard, the shaft may capture the
secondary member between the first and second capturing members. A
distance between the first and second capturing members may be greater
than the length of the shaft.

[0022]Further areas of applicability of the present invention will become
apparent from the detailed description provided hereinafter. The various
features, arrangements and embodiments discussed above in relation to
each aforementioned aspect may be utilized by any of the aforementioned
aspects.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023]FIG. 1 is a partial cross sectional view of an embodiment of a
fastener that includes a secondary member.

[0025]FIG. 3 is a partial cross sectional view of an embodiment of a
fastener in the form of a pin.

[0026]FIG. 4 is a partial cross sectional view of the fastener of FIG. 1
after it has experienced a partial failure.

[0027]FIG. 5 is a partial cross sectional view of the fastener of FIG. 1
after it has experienced a partial failure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028]Briefly, embodiments of the present invention are directed to
fasteners, hardware and related methods. Particularly, embodiments
described herein provide for fasteners that include secondary members
that may aid in inspection procedures and fastener part retention in the
event of breakage. For example, fasteners and methods disclosed herein
may be operable to retain portions of the fastener upon breakage, thereby
preventing potential further damage to equipment or injury to persons due
to uncontrolled fastener portions.

[0029]For example, such a fastener may be used in critical applications
where relatively frequent inspection is used to verify the integrity of
the fastener. Such applications may include, inter alia, aircraft and
other transportation systems, industrial machinery, construction and
excavation equipment, and amusement park rides. These and other
applications may require frequent inspection (e.g., daily) to ensure the
safety and proper operation of equipment.

[0030]For example, such a fastener may be used in critical applications
where uncontrolled fragments from broken fasteners may lead to further
damage or injury. In the example of a bolt, the failure is often near the
head, such that the head of the bolt may break away from the remainder of
the fastener. In aircraft for example, portions of broken fasteners could
fall into critical equipment, such as the turbine blades of a jet engine,
potentially causing catastrophic damage. Also, portions of broken
fasteners falling from significant heights could cause injury or damage
to property. In another example, portions of the amusement park
attractions may be traveling at significant speeds and/or occupying
significant heights with numerous patrons and workers in proximity. In
such an example, it may be highly desirable to retain portions of broken
fasteners (e.g., retain a broken head so that it remains with the shaft
of the fastener) to prevent injury.

[0031]The fasteners described herein have several advantages over existing
fastener retention systems. For example, many existing fastener retention
systems comprise several individual parts that must be assembled after
the primary fastener is installed. Such systems may require brackets to
be attached onto assemblies where the brackets function to restrain
portions of the fastener in case of fastener breakage. Such brackets may
require additional fasteners, washers, and/or other parts after the
primary fastener has been installed. Such systems may require additional
labor to install the additional parts after installation of the primary
fastener. Such systems may partially or fully obscure the underlying
fastener, thus hampering and/or preventing inspection. Such systems may
not be operable to retain portions of broken fasteners where the portions
are particularly small (e.g., where a head portion of a fastener
separates from the remaining portion of the fastener).

[0032]In contrast, and as discussed in detail below, embodiments of the
fasteners described herein may be installed without the need for the
installation of additional parts such as brackets, clips, or other
retention devices. Accordingly, installation and removal times for the
embodiments of fasteners described herein may be less than known fastener
retention systems. Furthermore, embodiments of fasteners described herein
may be inspected without the need to remove other parts. Furthermore,
embodiments of fasteners described herein may be stocked as a single part
and thus not require the additional stocking and handling of additional
parts such as brackets, clips, or other retention devices.

[0033]Although generally discussed herein in terms of a bolt with safety
retention capabilities, features and aspects described herein may be
applied to other fastener and hardware types. For example, fasteners such
as pins, screws, axles rods, and/or other hardware (e.g., any elongate
member that may be straight or curved) may utilize the secondary members
and capturing members described herein.

[0034]FIG. 1 is a partial cross sectional plan view of an embodiment of a
fastener 100. The fastener 100 of FIG. 1 is in the form of a bolt. FIG. 2
is an end view of the bolt of FIG. 1. Returning to FIG. 1, the fastener
100 includes a shaft 101 that has a first end 102 and a second end 103.
The shaft 101 is oriented along a longitudinal axis 104 that passes
through the center of the shaft 101. The shaft 101 may include a threaded
area 105 at the second end 103 of the shaft 101. The shaft 101 may also
include a head 106 disposed at the first end 102. The shaft 101 may be
generally cylindrical in the area of the shaft 101 between the head 106
and the second end 103.

[0035]The shaft 101 may be constructed from any appropriate material
generally used in fasteners. For example, the shaft 101 may be
constructed from steel. The shaft 101 may be manufactured to a particular
standard such as, for example, an SAE grade, an ASTM standard, and/or a,
DIN standard. The diameter and length of the shaft 101 may be sized to
match a particular application, which may depend on, for example,
strength and space requirements.

[0036]Although the shaft 101 of FIG. 1 is in the form of a bolt, other
types of fasteners may incorporate features and aspects described herein.
For example, and as shown in FIG. 3 described below, features and aspects
of the present invention may be incorporated into a pin such as fastener
300. Furthermore features and aspects of the present invention may be
incorporated into other types of fasteners and hardware.

[0037]The threaded area 105 may include any appropriate thread
configuration. For example, the threads may be fine pitch or coarse pitch
threads as known to those skilled in the art. Other types of threads may
also be used. The threaded area 105 may mate with a nut, such as a hex
nut, wing nut, locking nut, or any other appropriate type of nut. The
threaded area 105 may mate with a threaded hole. The threaded hole may be
a through hole or a blind hole. In a particular application, the fastener
100 may be installed with any appropriate additional hardware such as,
for example, flat washers and/or lock washers.

[0038]The head 106 of the shaft 101 may, be any appropriate shape. For
example, and as illustrated in FIGS. 1 and 2, the head 106 may be
hexagonally shaped for engagement with an appropriate tool (e.g. wrench,
socket). The head 106 may be configured using other appropriate shapes
(e.g., square). The head 106 may perform those functions typically
associated with the head of a fastener, such as enabling the fastener to
be driven by a mating tool and providing a surface on the underside of
the head capable of exerting a force on members to be fastened by the
fastener.

[0039]The fastener 100 includes a through hole 107 disposed along the
longitudinal axis 104 of the shaft 101 and extending the full length of
the shaft 101. The through hole 107 may be round in cross section. The
through hole 107 may be along the longitudinal axis 104 as illustrated or
it may be offset from the longitudinal axis 104. Other hole
configurations may be used, such as square or octagonal. The through hole
107 illustrated in FIG. 1 is of a single diameter along the entire length
of the shaft 101. Other hole configurations, for example with counter
bores or countersinks at one or both ends of the shaft 101, may be
utilized.

[0040]The fastener 100 of FIG. 1 further includes a secondary member 108.
The secondary member 108 may be disposed within a portion of the through
hole 107. As illustrated in FIG. 1, the secondary member 108 may be
disposed within the entire through hole 107 and extend beyond the first
end 102 and the second end 103 of the shaft 101. The secondary member 108
may be free from direct securement to the shaft 101. In this regard, the
secondary member 108 may be free to move within the through hole 107
relative to the shaft 101. Where the secondary member 108 and the through
hole 107 are both round, the outside diameter of the secondary member 108
may be smaller than the diameter of the through hole 107.

[0041]The secondary member 108 may be constructed from any appropriate
material. The secondary member 108 may be a flexible member or it may be
non-flexible. The secondary member 108 may be constructed from a single
rod of material. Alternatively, the secondary member 108 may comprise a
material comprising a plurality of individual portions, such as a wire
rope. Indeed, any appropriate material, such as wire, rope, cable, cord,
strap, and line may be used in the construction of the secondary member
108.

[0042]As noted above, the through hole 107 may include counterbores or
countersinks at either end of the shaft 101. In such a configuration, the
secondary member 108 may be of a length that exceeds the length of the
portion of the through hole 107 between the counterbores and/or
countersinks. In an embodiment where the secondary member 108 is longer
than the shaft 101, the secondary member 108 may include a first portion
of the secondary member 109 that extends beyond the first end 102 of the
shaft 101 and a second portion of the secondary member 110 that extends
beyond the second end 103 of the shaft 101. In such an embodiment, the
secondary member 108 may include a third portion between the first and
second portions of the secondary member 109, 110.

[0043]The fastener 100 may include a first capturing member 111 and a
second capturing member 112. As shown in FIG. 1, the first and second
capturing members 111, 112 may be in the form of balls or other
appropriately shaped members swaged onto (or attached in any other
appropriate manner) and fixedly secured to the secondary member 108. The
capturing members 111, 112 may be sized so that they are incapable of
passing through the minimum cross-sectional size portion of the through
hole 107. For example, the capturing members 111, 112 when in the form of
a ball swaged onto the secondary member 180, may have a diameter that is
larger than the minimum diameter of the through hole 107.

[0044]Accordingly, when fixedly secured to the secondary member 108, the
first and second capturing members 111, 112 may prevent the secondary
member 108 from moving out of the through hole 107. Although illustrated
and described as balls swaged to the secondary member 108, the capturing
members 111, 112 may be of any appropriate configuration capable of
fixedly attaching to the secondary member 108 while not being capable of
passing through the through hole 107.

[0045]In an embodiment, the first and/or the second capturing member 111,
112 may be formed from the secondary member 108 itself. For example,
where the secondary member 108 is a wire rope, a portion of the secondary
member 180 may be tied into a knot to form one of the capturing members
111, 112. For another example, the secondary member 108 may be swaged,
crimped, bent and/or otherwise deformed to form one of the capturing
members 111, 112 into a structure that is incapable of passing through
the through hole 107. In another example, the secondary member 108 may be
formed by soldering or welding the secondary member 108 such that a
bulbous portion forms the first and/or second capturing member 111, 112.

[0046]The first and second capturing members 111, 112 may be positioned to
allow room for a tool to attach/create the first and second capturing
members 111, 112. This is discussed further below in relation to a method
of manufacturing the fastener 100.

[0047]FIG. 3 illustrates an alternate embodiment of a fastener 300. The
fastener 300 of FIG. 3 is in the form of a pin. Many features of the
fastener 300 are similar to those of the fastener 100 of FIG. 1 and
therefore will not the repeated. The fastener 300 includes a shaft 301
with a first end 302 in the second end 303. A head 306 may be positioned
at the first end 302 of the shaft 301. Since the fastener 300 is in the
form of a pin, the head 306 need not be of a drivable configuration.
Accordingly, the head 306 may be round as shown in FIG. 3 or the head 306
may be of any other appropriate shape.

[0048]The shaft 301 may be cylindrical and include a retention feature
305. The retention feature 305 may be a notch that encompasses the entire
circumference of the shaft 301. The retention feature 305 in the form of
a notch may provide an area where a clip (e.g., c-clip) may be
interconnected to the shaft 301 after the fastener 300 has been inserted
into an assembly, thereby capturing the assembly between the clip
inserted into the retention feature 305 and the head 306. As in the
fastener 100 described above, the fastener 300 may include the
longitudinal axis 104, through hole 107, secondary member 108, first
capturing member 111, and second capturing member 112, all of which may
be similarly configured as described above with reference to the fastener
100.

[0049]Although illustrated as cylindrical, the shaft 301 may be configured
in any appropriate shape. For example, the shaft 301 may be square.
Although as illustrated as a circumferential notch, the retention feature
305 may take the form of any appropriate the feature operable to provide
a location to install a member to limit the movement of the fastener 300
once is it is installed. For example, the retention feature 305 may be in
the form of a straight notch disposed across a portion of the diameter of
the shaft 301 where a corresponding member inserted into the sttaight
notch may limit axial movement of the fastener 300. Also, in place of the
head 306 may be another notch such as notch 305. Additionally, the
fastener 300 may be designed for press fit applications in which case one
or both ends may be without a notch and/or a head.

[0050]Such a fastener 300 may be used to secure parts together along the
direction of the longitudinal axis 104 while allowing the secured parts
to pivot or rotate relative to each other. In another example, the
fastener 300 may be used to secure a wheel or pulley to another member in
a manner that allows the wheel or pully to rotate relative to the other
member.

[0051]A method of the fabrication of the fastener 100 of FIG. 1 will now
be described. The first step in the process may be to manufacture a bolt
in the desired configuration according to known manufacturing methods.
For example, a bolt similar to the fastener 100 of FIG. 1, but without
the through hole 107, may be made by casting and/or machining a bolt
from, for example, steel. The through hole 107 may then be formed within
the shaft 101 by drilling one or both ends of the shaft 101.
Alternatively, the through hole 107 may be formed at the same time that
the bolt is formed (e.g., through hole 107 may be formed at the time of
the original casting of the shaft 101).

[0052]The next step in the process of fabricating the fastener 100 may be
to insert the secondary member 108 into the through hole 107 at the first
end 102 of the shaft 101 until a portion of the secondary member 108
extends beyond the second end 103. This may be followed by
attaching/forming the second capturing member 112 to the second portion
of the secondary member 110 that is extending beyond second end 103. This
attaching/forming step may be performed with the second capturing member
112 attachment point to the secondary member 108 positioned at any
convenient distance away from the second end 103. In this regard, after
the second capturing member 112 is secured, the secondary member 108 may
be pulled in the direction of the first end 102 to bring the second
capturing member 112 into contact with the second end 103 of the shaft
101 as illustrated in FIG. 1.

[0053]The next step may be to attach the first capturing member 111 to the
first portion of the secondary member 109 that extends beyond the first
end 102 of the shaft 101. It may be desirable to pull the second
capturing member 112 up against the second end 103 so that the first
capturing member 111 may be interconnected to the secondary member 108 as
close as possible to the second capturing member 112 thus minimizing the
length of the secondary member 108 between the first capturing member 111
and the second capturing member 112. However, a distance between the
first capturing member 111 and the first end 102 of the shaft 101, such
as the distance illustrated in FIG. 1, may be required to allow clearance
for a tool (e.g., a swaging tool) to install the first capturing member
111 onto the secondary member 108. It will be appreciated that some
clearance between the first capturing member 111 and the first end 102
(e.g., the length of the secondary member 108 between the first and
second capturing members 111, 112 is longer than the shaft 101) may be
desirable for functional and inspection related functions as described
below.

[0054]Although described above as being assembled in a particular order,
the order of which end of the shaft 101 the secondary member 108 is
inserted into first and which secondary member 111, 112 is interconnected
first may be altered. Although the above description of the manufacturing
method was described in terms of the fastener 100 of FIG. 1, it will be
appreciated that similar techniques may be used to manufacture other
types of fasteners disclosed herein (e.g., the pin of FIG. 3).

[0055]The embodiments of fasteners described herein may be assembled as
described above and then stored for later use in a manner similar to
other fasteners. This is in contrast to some known fastener retention
systems which require the storing of the bolt itself, storing clips or
brackets used to retain the bolts once they are in an installed position,
and storing any hardware, such as screws or washers, that may be needed
to secure the clips or brackets such that they are operable to retain the
bolts. Furthermore, some known fastener retention systems required
additional machining in the area of the bolt to be retained. This may be
in the form of additional tapped holes or through holes to which the
retention hardware may be fastened. In contrast, the embodiments of
fasteners described herein may not require any additional machining or
configuration to areas around the fastener.

[0056]The embodiments of fasteners described herein may include the safety
retention features described herein, yet require no additional labor to
install such as required by many known fastener retention systems. For
example, some known fastener retention systems may require the additional
installation of clips or brackets and fasteners to attach those clips or
brackets that may be required after the original installation of the
primary fastener. In contrast, embodiments of fasteners described herein
do not require the labor to attach additional components after the
initial installation. Indeed, embodiments of fasteners described herein
may not require any additional labor beyond that needed to install any
standard fastener (e.g., a typical bolt). Furthermore, embodiments of the
fasteners described herein may be operable to be installed using
standard, commonly available tools, such as wrenches (e.g., open-end
and/or box wrenches), and sockets. Embodiments of the fasteners described
herein may be used in most applications where standard fasteners are
currently used. For example, embodiments of fasteners described herein
may be used with standard nuts, wing nuts, locking nuts, through holes,
and blind holes.

[0057]As described, embodiments of fasteners disclosed herein include a
through hole 107 extending through the shaft 101 along the longitudinal
axis 104. Such a through hole 107 may be relatively small in diameter
relative to the diameter or cross-sectional size of the shaft 101. In
this regard, the through hole 107 may have a relatively small impact on
the overall strength of the fastener 100. For example, in an embodiment,
the ratio of the minimum outer cross-sectional dimension of the shaft 101
to the diameter of the through hole 107 may be at least 6 to 1. If the
relatively small impact of the through hole 107 on the overall strength
of the fastener 100 is a concern in a particular application, the
strength of the fastener 100 may be increased. This may be accomplished
by, for example, increasing the overall size of the shaft 101 and/or
choosing a higher strength material for the fastener 100.

[0058]In the event of a failure of the shaft 101, the secondary member 108
may prevent portions of the fastener 100 from separating fully from the
assembly in which the fastener 100 is incorporated. For example, where
breakage occurs in the shaft 101, individual separate portions of the
shaft 101 will be retained by the secondary member 108 when the
individual portions include a portion of the length of the through hole
107. In this regard, the first and second capturing members 111, 112 may
retain the broken pieces of the shaft 101 between them and along the
secondary member 108.

[0059]For example, a known mode of failure for a bolt is where the head
separates from the shaft at the interface between the head and the shaft.
Such a failure is illustrated in FIG. 4, which illustrates the fastener
100 of FIG. 1 after breakage. In the configuration shown in FIG. 4, the
broken fastener 400 was installed with a nut 402 and positioned to hold
together a first member 403 and a second member 404 (shown in cross
section) such that the first member 403 and second member 404 were in
direct contact with each other. FIG. 4 illustrates a separation between
the first member 403 and the second member 404 after breakage of the
fastener 400. The head 106 has separated from the remaining portion of a
broken shaft 401 at a fracture point 405 at the interface between the
head 106 and the rest of the shaft 401. In such a case, both the head 106
and the shaft 401 may remain disposed about the secondary member 108 and
confined to the portion of the secondary member 108 between the first and
second capturing members 111, 112. Accordingly, the head 106 will not be
able to separate from the remaining portion of the faster 400, thus
potentially preventing further damage or injury.

[0060]The secondary member 108 may be sufficiently flexible and/or
compliant such that it is capable of withstanding forces that may result
in and/or from breakage of the shaft 401. This may result in the
secondary member 108 not failing even though the surrounding shaft 401
experiences breakage.

[0061]For example, the fastener 400 in tension may fail due to the tension
or the tension coupled with other forces (e.g., from vibration, shock,
etc). The failure may result in a separation of the broken parts by a
small distance 407. This distance 407 may be less than or equal to the
slack between the first and second capturing members 111, 112 and the
shaft 401. Therefore, only a portion or none of the shock of breakage may
be translated to the secondary member 108. As illustrated in FIG. 4, the
secondary member 108 may remain in tact and operable to confine the
broken pieces of the fastener 400. As previously noted such retention
capabilities may be beneficial in certain applications (e.g., amusement
park attractions, aircraft).

[0062]In addition to the retention of broken portions of the fastener 400,
the secondary member 108 may also be operable to retain some capabilities
with respect to the primary function of the fastener 400. For example, as
illustrated in FIG. 4 where the fastener 400 is being used to hold two
members 403, 404 together and the shaft 401 fails as described above, the
ability of the secondary member 108 to retain the head 106 proximate to
the shaft 401 and the strength of the secondary member 108 may allow the
fastener 400 to continue to hold the two members 403, 404 in proximity to
each other. Of course, in such a scenario, the two members 403, 404 may
not be held together with the same compressive forces as when the
fastener 400 was intact. However, the secondary member 108 may be
operable to temporarily hold the two members 403, 404 together until
subsequent discovery of the failure and repair.

[0063]After a failure, such as the failure described above where the head
106 separates from the remaining portion of the shaft 401, a visual
inspection may readily reveal the breakage if the head is loosely held
proximate to the shaft 401. However, if the members 403, 404 being held
together separate (e.g. as illustrated in FIG. 4) such that the head 106
is disposed against one of the members 403, 404, or if the shaft 401 were
to break along a portion of the shaft 401 that is not readily visible by
inspection (e.g., in the transition 405 between the non-threaded portion
of the shaft 401 and the threaded area 105). a visual inspection may not
readily reveal the breakage. After such a breakage, the individual
portions of the shaft 401 may separate and take up the slack in the
secondary member 108 such that both the head 106 and the second end 103
of the shaft 401 are positioned against the first and second capturing
members 111, 112 respectively. In such a case, a visual and/or tactile
inspection of the fastener 400 may reveal that, as illustrated in FIG. 4,
no slack exists in the secondary member 108, thereby indicating a
potential failure of the fastener 400. In particular, an inspector may
touch and/or attempt to move one of the exposed capturing members 111,
112. If such an inspection reveals no slack and/or looseness of the first
and/or second capturing member 111, 112 relative to the shaft 401 the
inspector may further inspect the fastener 400 (e.g., by removing the
fastener 400 from its installation). If such an inspection reveals less
than the expected amount of slack and,/or looseness this may indicate a
potential failure and warrant further inspection. Conversely, where the
inspection reveals the expected amount of slack and/or looseness of the
secondary member 108 and first and/or second capturing members 111, 112,
this may be an indication that no gap and/or breakage exists, as in the
shaft 101 of FIG. 1. Such inspection techniques may represent a potential
improvement over the prior art, where a clip or bracket covering the head
of a bolt that may retain the head in the event of failure may also
restrict access to the bolt and therefore require removal of the clip or
bracket to inspect the underlying bolt.

[0064]FIG. 5 illustrates the fastener 100 of FIG. 1 after a breakage of a
different type than illustrated in FIG. 4. In the configuration shown in
FIG. 5, the broken fastener 500 was installed with a nut 402 and
positioned to hold together a first member 403 and a second member 404
(shown in cross section) such that the first member 403 and second member
404 were in direct contact with each other. FIG. 5 illustrates a relative
lateral shift in position between the first member 403 and the second
member 404 after breakage of the fastener 500. A first portion 501 of the
fastener 500 has broken from a second portion 502 at the interface
between the two members 403, 404. This may represent a failure mode where
the fastener 500 failed at least in part due to shearing forces between
the two members 403 and 404. In such a case both the first portion 501
and the second portion 502 may remain disposed about the secondary member
108 and confined to the portion of the secondary member 108 between the
first and second capturing members 111, 112. Accordingly, neither the
first portion 501 nor the second portion 502 may be able to separate from
the assembly, thus potentially preventing further damage or injury.

[0065]After a failure such as illustrated in FIG. 5, a visual inspection
may not readily reveal the breakage. However, after such a breakage, the
first and second portions of the shaft 501, 502 may separate and take up
the slack in the secondary member 108 such that a tactile inspection of
the fastener 500 may reveal that reduced slack or no slack exists in the
secondary member 108, thereby indicating a potential failure of the
fastener 400. Moreover, if the first and second portions 501, 502 have
shifted relative to each other enough that the secondary member 108 is
pinched at the interface between the first portion 501 and the second
portion 502, the secondary member 108 may be incapable of moving relative
to the fastener 500. Accordingly, a tactile inspection may reveal such a
lack of mobility of the secondary member 108.

EXAMPLE

[0066]In one particular embodiment of the present invention, the shaft
comprises a 3/4-10×6'' Grade 8 steel bolt with a 0.109 diameter
through hole along the longitudinal axis of the bolt. The resulting ratio
of the shalt size to the hole size is approximately 6.9 to 1. Within the
through hole is disposed a stainless steel aircraft quality wire rope
comprising seven strands, each comprising 19 wires. At both ends of the
wire rope, a 0.288'' diameter stainless steel ball is fixedly attached
(e.g., crimped, swaged) to the wire rope. The slack between the balls and
the bolt (e.g., the difference between the length of bolt and the
distance between the two balls along the wire rope) is between 0.09'' and
0.15''. In the present particular embodiment the slack may be required to
accommodate clearances for the tool used to attach the balls to the wire
rope. Furthermore, the wire rope may extend a maximum of 0.062'' beyond
the balls. In the present particular embodiment this distance may be
required to accommodate tooling used to cut the wire rope after the balls
are fixedly attached to it.

[0067]Although the above-described fasteners and methods have generally
been described in terms of a bolt, other types of fasteners and/or
hardware may incorporate the features and methods taught herein. For
example, screws, pins, and axles may incorporate secondary members and
capturing members and thereby gain some or all of the above-described
advantages such as, for example, ease of inspection and retention after
breakage.